Author: Geek Computer
Tuesday, January 7, 2020

What Is BIOS?

When I was a new computer user, I didn’t know how important the BIOS (Basic Input/Output System) was to the functioning of my PC. My thinking changed when I found out that the BIOS transforms a computer from a metal box to something that can execute and interpret commands. For example, computers cannot identify electric currents without the help of the BIOS. If the BIOS is not present, the electric current will run freely around the motherboard. 

What is BIOS? BIOS is a piece of code located in the motherboard and contained in a ROM chip. Through the BIOS, a user can set up and configure their systems at a basic level. When you switch on your computer, the first thing that runs in the BIOS. Then, before the computer connects to the operating system (OS) for more instructions, the BIOS identifies the hardware in your computer, which is then configured and tested. This is known as the booting process. 

What Is BIOS?

The Purpose of BIOS

The primary function of the BIOS is to make sure the startup process of the computer happens smoothly. This ensures the correct loading of the operating system into memory. The BIOS is essential in the operation of modern computers. Getting to know about how it functions can save you time when troubleshooting issues with your PC. 

  • POST: After switching on your computer, thBIOS's first job is the Power On Self Test (POST). During this process, computer hardware is scrutinized by the BIOS to ensure that the startup process will be successful. If the POST process is completed, a beep will be emitted from the system. However, if the process is unsuccessful, the system emits a series of beeps. Using the number, pattern or duration of these beeps, you can identify the reason for failure.

  • STARTUP: When the POST process is completed, the BIOS, through the bootstrap loader, will attempt to start the operating system. The bootstrap loader has been designed to detect available operating systems. If the OS found is legitimate, it will be loaded into memory. At this point, BIOS drivers are also loaded. With the help of these drivers, the computer has basic control over peripheral devices (e.g., keyboard and mouse), storage devices, and network hardware.

  • SECURITY: The BIOS can also help to maintain the security of your computer. You can use it to password protect the boot process; this means that a password is required before any BIOS activity occurs. If you want to password protect the full operations of your PC, this is a very effective method to apply. 

  • HARDWARE: Considering it is the first software that takes control of your computer during the boot process, the BIOS software location is very important. If the BIOS is not located in the same place as a ROM chip, the boot process will be unsuccessful because the computer’s microprocessor will fail to locate it. 

The Booting Process and BIOS

When you turn on many computers, texts describing the amount of memory you have installed or the type of disk available pop up. This is an example of your BIOS at work and trying to get your computer to run. The BIOS's first thing is to check the CMOS (Complementary Metal Oxide Semiconductor) setup for any custom settings and loads the interrupt handlers. It then checks if the video card is functional. Next, the BIOS determines if it is a reboot or a cold boot by checking the memory address value 0000:0472. If a value of 1234h is indicated, it is a reboot and the BIOS will skip the remaining POST process. Any other value is interpreted as a cold boot.

If the result is a cold boot, a read or write test is conducted by the BIOS on each memory address to verify the RAM. Next, the USB ports are checked for a mouse and keyboard. It then looks for a PCI (Peripheral Component Interconnect) bus and, if found, checks the PCI cards. Finally, if any error occurs during the POST process, the BIOS will notify you using screen text display or a series of beeps. 

The BIOS then shows you some of your system details. This includes information about memory, display, hard drive, the processor and BIOS revision. Using the CMOS setup as a guide, the sequence of storage devices marked the BIOS scrutinizes boot devices. From the first device listed, the BIOS attempts to initiate the boot sequence. If a device is not found, the BIOS will try the next listed device. If a device lacks the proper files, the startup will halt. If the correct system files are not found, the process will not continue.

How to Access and Use BIOS

Getting access to the BIOS is not hard. The first thing that you are required to do is to restart your computer. If your computer is off, press the “on” button. Then, wait for the first startup screen to appear. Once it appears, you will have a very short time-frame to press the BIOS setup key. If you miss this step, you will have to restart your computer and try again. If you wish, you can start pressing the setup button as the computer starts to reduce chances of failure. 

By tapping [Del] or [F2], you will be able to enter the setup. You should note that the key you will be prompted to press might differ based on the model and make of your computer’s motherboard. It might be [F8], [Esc], [F10] or [Tab]. Usually, the “F” keys (located at the top of your keyboard) are the ones used to access the BIOS. If none seem to work and no prompt appears, you can check your computer model’s manual or your online support page. 

The BIOS supports several hardware configuration options. The setup utility can be used to change these options. To apply these changes to the BIOS, you will need to save them and restart the computer. Several things can be achieved through the BIOS system:

  • Creating or removing a BIOS password
  • Changing the boot process order
  • Changing the hard drive settings
  • Altering the date and time
  • Disabling or enabling the computer logo 
  • Altering system voltages, among others. 


What Is BIOS?

Can a BIOS Be Updated or Upgraded?

The only way to add extra memory as an upgrade to a BIOS chip is through removing it physically to replace it with a new and more advanced ones. If it is a flash BIOS, the data can be updated to add new features or fix problems in the motherboard. However, this can only be done through the help of a specially designed software. In order to determine the BIOS version on your PC, you will need to access the BIOS setup. The BIOS version and type should be displayed on the main BIOS screen. 

The limitations present in the BIOS have led to the development of a firmware interface known as the UEFI (Unified Extensible Firmware Interface).  It has been designed to replace the BIOS. The BIOS and UEFI are very similar, but the UEFI has more advantages. For example, the UEFI can boot from disks with a 2TB+ size, has forward and backward compatibility, and a graphical interface with network access.


The BIOS is a piece of code contained in a ROM chip that is located on the motherboard. When you turn on your PC, the BIOS is the first thing to run. The main function of the BIOS is to ensure the startup procedure of a computer runs smoothly. To be able to configure your system at a basic level, knowledge of how to operate the BIOS is essential. Understanding the BIOS can also help you deal with a number of your computer related issues. For example, the BIOS can be accessed at the beginning of a computer’s booting process. If you are not keen enough and you miss the step and need to restart your computer. Due to the limitations present in the BIOS, it will soon be replaced by the UEFI.

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